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==='''Spontaneous''' [[genetic mutations]]===
==='''Spontaneous''' [[genetic mutations]]===
These mutations change the [[gene]]s within the [[chromosome]]s of the organism and can result in new [[polypeptides]] being produced. These abnormal polypeptides can have significant affects on the biochemistry of the organism, for example [[sickle cell anemia]] occurs because one [[base]] within the gene for beta-[[hemoglobin]]. Mutations may occur for several reasons such as [[chemical]] [[mutagens]] or exposure to [[ionizing]] [[radiation]], or because of errors made when DNA is copied inside a cell at the first stage of [[mitosis]]. Although most mutations are harmful due to their random nature (see the example regarding sickle cell anemia), beneficial mutations may also occur.
These mutations change the [[gene]]s within the [[chromosome]]s of the organism and can result in new [[polypeptides]] being produced. These abnormal polypeptides can have significant affects on the biochemistry of the organism, for example [[sickle cell anemia]] occurs because one [[base]] within the gene for beta-[[hemoglobin]]. Mutations may occur for several reasons such as [[chemical]] [[mutagens]] or exposure to [[ionizing]] [[radiation]], or because of errors made when DNA is copied inside a cell at the first stage of [[mitosis]]. Although most mutations are harmful due to their random nature (see the example regarding sickle cell anemia), beneficial mutations may also occur.
Mutations will not be inherited unless the affected cells are [[gamete]] producing cells or gametes themselves
For example, there may be a spontaneous mutation in a [[germline]] ([[gamete]] producing) cell of an agouti (brown) rabbit that changes the allele so that it produces a polypeptide that dyes fur white and produces an [[albino]] rabbit. There are also alleles that produce chinchilla and Himalayan coats<ref>Biology 2, Jones M. & Gregory J., 2001, Cambridge University Press, ISBN 0-521-79714-4</ref>
For example, there may be a spontaneous mutation in a [[germline]] (gamete producing) cell of an agouti (brown) rabbit that changes the allele so that it produces a polypeptide that dyes fur white and produces an [[albino]] rabbit. There are also alleles that produce chinchilla and Himalayan coats<ref>Biology 2, Jones M. & Gregory J., 2001, Cambridge University Press, ISBN 0-521-79714-4</ref>
==='''[[Meiosis]]''' and random [[fertilization]] of gametes===
==='''[[Meiosis]]''' and random [[fertilization]] of gametes===